Max Planck Institute for the Science of Light, Günther-Scharowsky-Strasse 1, 91058 Erlangen, Germany.
Phys Rev Lett. 2013 Jul 19;111(3):033902. doi: 10.1103/PhysRevLett.111.033902.
Modulational instability (MI) of 500 fs, 5 μJ pulses, propagating in gas-filled hollow-core kagome photonic crystal fiber, is studied numerically and experimentally. By tuning the pressure and launched energy, we control the duration of the pulses emerging as a consequence of MI and hence are able to study two regimes: the classical MI case leading to few-cycle solitons of the nonlinear Schrödinger equation; and an extreme case leading to the formation of nondispersing subcycle pulses (0.5 to 2 fs) with peak intensities of order 10(14) W cm(-2). Insight into the two regimes is obtained using a novel statistical analysis of the soliton parameters. Numerical simulations and experimental measurements show that, when a train of these pulses is generated, strong ionization of the gas occurs. This extreme MI is used to experimentally generate a high energy (>1 μJ) and spectrally broad supercontinuum extending from the deep ultraviolet (320 nm) to the infrared (1300 nm).
在充满气体的中空 kagome 光子晶体光纤中传播的 500fs、5μJ 脉冲的调制不稳定性（MI）进行了数值和实验研究。通过调节压力和发射能量，我们控制了由于 MI 而产生的脉冲的持续时间，从而能够研究两个 regime：导致非线性薛定谔方程中少周期孤子的经典 MI case；以及导致形成非色散亚周期脉冲（0.5 到 2fs）的极端情况，其峰值强度约为 10(14)W/cm(-2)。通过对孤子参数的新的统计分析，可以深入了解这两个 regime。数值模拟和实验测量表明，当生成这些脉冲的 train 时，气体发生强烈的电离。这种极端的 MI 用于实验生成高能（>1μJ）和光谱宽的超连续谱，从深紫外（320nm）延伸到红外（1300nm）。
